Clinical Use
Diagnosis of pancreatic endocrine tumours.
Application
Pancreatic polypeptide (PP) production is most commonly associated with tumours producing vasoactive intestinal polypeptide and with carcinoid syndrome and, less commonly, with insulinomas and gastrinomas.
Patient Preparation
Fast the patient completely overnight. Take blood (10 mL) using a syringe and needle.
Sample Preparation
Transfer the blood (10 mL) to a heparin tube (do not exceed 20 U/mL blood) containing Trasylol (aprotinin, 0.2 mL, 2000 KIU). Mix by inversion. Place on ice and transfer to the laboratory. Separate the plasma in a refrigerated centrifuge. Visible haemolysis invalidates the result. Freeze the plasma at -20C within 15 min of venepuncture. Send plasma (5 mL) to the SAS laboratory. Ensure the sample remains frozen during transport.
Reference Ranges
Adults (fasting): <300 pmol/L;
Adults with endocrine tumours producing PP: >300 pmol/L.
About 50% of patients with pancreatic endocrine tumours have elevated values for plasma pancreatic polypeptide. Adults with strong vagal tone or after a recent meal may have values >300 pmol/L. Pancreatic polypeptide is also found to be at the upper limit of normal in elderly patients.
Centre offering this assay
London Imperial Charing Cross Hospital Endocrine Laboratory